Method of testing lubricants



Jan. 25, 1938. v FAV|LLE 2,106,170 4 METHOD OF TESTING LUBRICANTS 7 Filed April 20. 1936 I s Sheets-Sheet 1 Jan. 25 .1938. F. A. FAVILLE METHOD OF TESTING LUBRICANTS Filed April 20, 1936 '3 Sheets-Sheet 2 6 +1 -E g 5 a" .55 50 I '24 I. 5? 42 v2 i5 WHIHHIHIHIH|HH|| f ab- 1 b L uu Egg, 9 87 57 F I if g /0 /fl5 2/44 Ill?! IMI \\\\VIII,

Jan. 25, 1938. F. A. FAVILLE METHOD OF TESTING LUBRICANTS Filed April 20, 1936- 3 Sheets-Sheet 5 Patented Jan. 1938 UNITED {.srA'ras PATENT OFFICE a aicu'i'o V EMETHOD'OF mama wnarcim'rs- Frederick A. Favllle, cum, in. Am oaflon April 20, ms, Serial No. 15.!

i Claims. (Ol n-5U This invention relates to a method of testing lubricants and more particularly to a method wherein the rate of wear between standard bearing surfaces for anygiven lubricant having extreme pressure, or so-called' E. P. value, maybe determined directly as the test proceeds and .without the necessity of stopping the test or waiting until the end of the test period tomeasure the amount of wearby the useo'i micrometers or a balance.

The type of machine that I I for carrying out my method of testing lubricants .for P. value is that described in the Mead Cornell application entitled Oil testing, ma-- chine", Serial No.- 17,581, filed April 22, 1935.

The present method constitutes an improvement, or advance over themethod described in that application in that the prese nt method permits Y a study of the qualities ofa givenlubricant, as

well as a direct comparison between different lu- 'bricantaduring the test period afterthe full fluid film of the lubricant has been broken and wear of the bearing surfaces occurs." My present method also provides means for directly determining the amount o'iwearof the-bearing'surfaces durlng'this period, and therefore therate of wear.

It is'therefore an important object of this invention to provide a method of testing lubricants whereby the E. P." quality of-a given lubricant may be determined during the period of pro-' nou'ncedwear between the bearing surfaces and after the full fluid-film of the lubricant has been;

ruptured. I It is a further important object of this invention to provide a method'for obtaininga direct reading of the amount of wear between bearing surfaces under constant load during the testing of a given lubricant. and without interrupting. the test or waiting until the end. of the test'period to measure the amount of wear.

It is a further important object of this invention to provide a method. for the direct com-- parison of diflerent lubricants, includinga meth- 45. d wherein diflerent'iubricants are diluted with Gil an inert oil having no E. P. value, so that stand-' ards can be set up for the grading of P. lu-

bricants and oils may be compounded to produce products of the desired E. P. values.

Other and further important obiects of thisinvention will become apparent from the following description and appended vclaims.

My invention is best illustrated by iei'erence to the accompanying drawings.

4 0n the drawings:

Figure 1 is a side elevation of a lubricant testing machine of. atype suitable for use in the carrying out of the method'embodying the principles of my invention.

'h'm' found suitable --Figure '2 is atop plan view oithe same, with parts broken away to show the driving gears. Figure 3 is an enlarged sectional view taken substantially o line m- -m 6: Fig.1, with parts talren substantially in elevation.

Figure 4 is a sectional view on line Ill-4V of Fig. 3, with 'partsln elevation.

.Figure 5 is an enlarged. sectional view taken amused..-

Figure 6 is a fragmentary, enlarged view, taken substantially alon'gthe line VI--VI of Fig. l,

with partsin section. Figure 7 is a sectional view along the line VII-N11 of Fig. 8, with parts in elevation.

Figure 8 is an enlarged detail view of the bearing pin assembly,

"Figures 9 and 10 are end and elevational views,

respectively, of a bearing block used in the ma-' chine of the other figures.

Figure li'is a sectional view ofthe bearing pin assembly, taken substantially along the line xr-xi of Fig. 7,- with parts in elevation and i1- lustrating the wearing of the pin bearing surface.

In order that the method of my invention may be clearly v understood, a machine suitable for use in the carrying out of such method will first I tially on line V- -V of FIG. 1, with parts,

taken substantially be described. It will be understood that the machine itself does 'not constitute a part of the present invention but is described and claimed in the Cornell application above referred to.

In Figs. 1 and 2, the reference numeral H indicates a base or supporting stand on which ap- "+20 'to-dependent lugs Il-il formed on a gear casing or housing 22.

- lugs lS-IQ, which are secured by means of bolts 7 Said motor iris provided with a drive shaft 23 carrying a pinion gear 24 secured thereto. A stub shaft 25, suitably journaled in the gear. $88- ing- 22, .has secured thereto a pair of gears, comprising a gear 28 meshing with the pinion gear 24 and another gear 21 that meshes with a gear 2 8 ona stubshaft 29. The gears 21 and I. are .lnterchanseable, or may be replaced by other pairs. of gears of varying numbers of teeth, sothat the speedmay lie-varied as desired. Either metal or iib'er' gears may be used.'. or combinations thereof, to reduce the noise of the drive mecha- Acoverplatel lisadaptedtobecappedonto 'ment with an eccentric disk 34 mounted on said shaft 29. Said arm 33 mayberemoved by merely unscrewing the nut 32.

The casing 22 may also be provided with laterally extending lugs H, with which is engaged a handle or ball I 1. The lugs .|4 are placed at approximately the center of mass of the apparatus so as to permit the machine to be carried by meansof the bail l1.

The bearing load applying mechanism comprises a pair of lever arms 38 and 31, which 'together constitute a jaw, and a transversely extending shaft 38, by means of which a load is applied to said levers 38 and 31 and by-them transmitted to the bearing surfaces. Said lever arms 38 and 31 are securely fixed upon stub shafts 39 and 48, respectively, by means of keys 4| and 42. Said stub shafts 39 and 48 are rotatably disposed within a block or housing 43,

which is pivotally mounted upon a cylindrical I tube 44 that houses the shaft 29; the upper end of said tube 44 being force'fitted or otherwise secured within the casing 22. A knurled bearing collar 45 isthreaded into the lower end of the tube 44 to form a bearing support for the block 43.

The transverse shaftv 38 is provided with threaded ends 48 and 41 that extend freely through bifurcated ends 48 and 49 on the lever arms 31 and 38, respectively (Fig. 3). The threaded end 48 extends through and is in threaded engagement with a member 58' that- .therewith and partially enclosing the bifurcated end 49 of the lever 38. A helical spring 58 surrounds the portion of the shaft 38 between an engaging face 51 of the member and a bear,- ing member 58. ,I'his'bearing member 58 is provided with a segmental spherical surface, 59 for engagement with a correspondingly formed surface'88 in the bifurcated end 49. The load'is thus applied through the spring 58 and the bearing member'58 to the bifurcated end 48 lever 38. I V The load applying lever 33 carries at its free end a dog or pawl 8| which is normallyin'gravity engagement with the teeth 83 of a ratchet of th e wheel 82 fixedly secured on the shaft 38. It will be apparent that when the motor I2 is driven to rotate the shaft 29, the eccentric throw of the disk 34 will effect a reciprocating movement of the load applying arm 33, so that the wheel 82 will be caused to rotate by the engagement between the paw1.8| and the teeth 83. A pivotally mounted trip member 88, positioned adjacent the end of the load applying arm 33 serves for manual adjustment of said arm 33 to' swing the pawl 8| out of engagement, or into-engagement with r the ratchet wheel 82.

v The housing 43 (Fig. 5) is provided with a laterally extending eye lug 88 for connection to a sylphon 81. Said eye lug 88 is internally threaded, as at 88, for engagement with the threaded end of 'a connecting member 89. The connecting member 89 is internally threaded as at 18 to receive a flanged plug 1|, which secures the connecting member 89 in the eye lug 88. The sylphon '81 is provided with an end boss 12 that extends through an opening 13 in the connecting member 89. A pressure transmitting plunger 14 is threaded into said end boss 12 and held therein by means of a lock washer 15. Said plunger 14 is provided with a conically shaped,

rounded end 18 centered in a conically shaped course, filled with a fluid, such as oil, glycerine,

or the like, for transmitting the pressure to the working mechanism of the gauge 88.

A second "gauge 8| is operatively connected to the load applying mechanism by means of a pin 82 (Fig. 4) carried by the bearing block 58. Said pin 82 actuates the working mechanism of the gauge 8| to cause the pointer 83 of, said gauge to show the jaw load in pounds. Before the spring 58 is inserted in place, it is calibrated to determine the amount of deflection produced by a given load acting to compress the spring. The gauge 8| is correspondingly calibrated to show the load placed upon the jaw arms 38 and 31 and by them'transmitted to the bearing surfaces. All deflection of said arms 38 and 31, as by bending, is thus automatically compensated for, since the gauge 8| indicates directly the compressive I load put upon the spring 58.

The driven shaft 29 carries at its lower end a bearing pin 84 (Fig. 6) secured therein by substantially identical, only one of them will be described. The bearing block holder 89, for instance, is provided with a transverse bore 83,

which is threaded, as at 84, inwardly from one end and provided with a counterbored socket 'at the other end, with a connecting smooth bore portion 98. A plug 91 is adapted to be threaded into the threaded bore portion 84 by means of a wrench (not shown) adapted to fit within the.

the block 81 is of slightly smaller dimensions than the counterbored recess 88, thereby permitting the block to be self-adjusting.

Each of the bearing blocks 81 and 88 has a V shaped notch I02, providing converging plane surfaces I03 and I04 (Figs. 9 and 10) for line of the bearing blocks 81- and 88 and of the balls I cause the bearing blocks 81 and 88 to be selfadjusting, so that centers of the balls I00 U and the axis of the pin 84 will always be in the same plane and the bearing forces acting against the pin 80 consequently will be properly balanced.

Means are provided for maintaining the bearing blocks 81 and 88 and the portion of the hearing pin 88 encompassed thereby beneath the surface of a lubricant to be tested. Such means include a post I05 (Fig. 1) on which is slidably and pivotally supported a platform 08. A spring i 01 normally holds the platform I06 inelevated positibn. On-the platform I08is mounted a tray I08 for containing the lubricant to be tested. The

normal level of the lubricant within the tray I08- is indicated by the dotted line I09 (Fig. 6).

In describing my method of testing lubricants on a machine such as here illustrated'and described, it will be unnecessary to describe in detail the method of testing a lubricant during the full fluid film period since one such method is; given in the Cornell application above referred to. The method of the present invention has to do with the testing of lubricants after the full fluid film of the lubricant has been ruptured during th preliminary test perioddes'cribed in the Cornell application. Consequently, although the preliminary test period will be briefly de-- scribed herein, it will be understood that the" present method has to do prlnclpally'with the testing of the lubricant during the wear period and after the full fluid film has been broken.

In starting up any test on a machine such as described, the pan 108 is filled with the lubricant to be tested up to the level indicated by the dotted line I00 (Fig. 6), or to such depth as will be sufficient to cover the bearing surfaces with the lubricant. After the blocks 8? and 88 have been positioned in the holders 80 and 90 in bearing engagement with thebearing pin 80, the pan I08 is moved up into position. The temperature of the lubricant should be about 210 F. at the start of the test period. or the bearings should be run in for a while at-a low load until approximately that temperature is reached, before starting the reading.

The ratchet wheel shaft 38 is then swung into place and the wheel 62 revolved in the proper direction to show airinitial registration oi zero on the gauge 8i. The load applying arm 83 is next moved into place to bring the pawl 8| into engagement with the teeth. 68 of the ratchet ratchet arm is then reengaged and the load run up to 500 lbs. for 1 minute, the ratchetarm disengaged and the torque noted. At the end oi" arm is again disconnected and the machine run As will-be readily appreciated, the E. Pavaluepanied' by a sharp pop-up in the torque gauge, which'in the average case, will jump-from a reading of say 30 to anything from 50 to 150, sometimes accompanied by squealing. with certain lubricants; it will be noted that pop-up occurs at a relatively low load, while with others it does not occur materially higher loads have been reached. In order to make. a fair comparison of therate of metal wear-after popup, it is necessary to make a wear test at a pre- If 1500 lbs. is. used as the starting load, itis advisable to continue the intermittent loading beyond the pop-up point until a 1500 lb. gauge load is reached. After pop-up, intermittent loading iscontinued, using only 30 second time intervals for each loading point after=pop-up occurs.

1i pop-up occurs at exactly 1500 lbs, gauge load, at least -1 full minute should elapse from the time of pop-up until timing for rate of wear .is' begun. .Should pop-up occur at loadsgreaterthan 1500 lbs. gauge, as at 2000 or 2250 lbs., it is After the load has worked up to 1500 lbs., or

the machine isrun for l inute at 1500 lbs., as in the case of pop-up at 1500 lbs., or the load has been worked back to 1500 lbs., as in the case stepped up on the of oils popping up .above 1500 lbs., the time is noted and the ratchet wheel 02 is marked at some convenient point, as'by means of a pencil laid across the loading arm 36 or 31. It is also convenient to. have the ratchet wheel 02 laid ofi in divisions of 10 teeth each, as by means of minutes operation. At the end of each minute of the three minute test period, the ratchet .wheel is marked by pencil and the numb :r of

teeth between'the successive marks is noted.

The number of teeth so noted is a direct measure of the amount of wear between the bearing surfaces of the pin 84 and blocks 81 and 88. An

amount of wear corresponding to teeth over' thethree minute test period may be considered asindicating good E. P. value.

As best shown in Fig. 11, most of the wear occurs on the pin 84, the amount of. wear being indicated by the reduced diameter ofthe cylindrical bearing surface 'I2I. The actual amount of wear can, of course,.be calipered, but it can equally well be expressed-in terms of number of teeth, as counted on the ratchet wheel. From the number of teeth and the wear expressed in inches, correspondingto one tooth, the actual wear in inches may be easily calculated, if desired, without the use ofcalipers.

gauge load at the time of pop-up, and less than 50 teeth on the E. P. film rating 3 minute test.

Another oil, supposedly E. P. but with a bad service record on hypoid type gears, showed a fluid film strength of 1000 lbs. gauge load but gave an E. P. film rating of over 250 teeth on successive tests, indicating inferior E. P. value.

In the case of another lubricant which passed the Gleason test with a high rating, the product showed a film strength of 2000 lbs. gauge load and an E. P. film rating of 60 to 65 teeth on four repeat tests.

With numerous lubricants. containing a certain type of oiliness addition agents, it will be noted that normal pop-up is extremely hard to detect, even though noticeable wear is observed at the point where normal pop-up should occur. Such lubricants are more easily studied by first diluting with a certain proportion of an inert diluent, such as an oilof no E. P. value. For instance, kerosene or any transmission oil having no E. P. value may be added in any desired proportion and the E. P. film rating of the thus diluted lubricant determined in the manner above described.

Tests on a large number of E. P. lubricants have demonstrated the ability by some lubricants to reestablish a full fiuid'film condition during the E. P. test period above described. In one case, for instance, the lubricant showed a wear of 62 teeth during the three minute test period, but,

upon continuing the test, showed only 23 teeth wear for the subsequent three minutes. This indicates a tendency to reestablish full fluid film.

In order to get a more accurate indication of E. P. value, the lubricant in question was diluted with 67% of ordinary water white kerosene distillate and tests run on the diluted product. Three repeat tests showed satisfactorily consistent evaluation figures.

It will be understood that as many variables as possible should be eliminated in making comparative tests on different lubricants. It is preferable, for instance, in carrying out the test methods above described to revolve the test bearing pin at a definite speed, such as 290 R. P. M., and

150 startwith the lubricant at a definite tem- 'ing into the E. P. film. and also due to formation of a slip-film condition similar't'o that observed when a cutting drill is turned so fast that it will not out.

Extreme pressure products are characterized by their ability to resist welding of the bearing surfaces. The action of the lubricant in the test machine above described during the E. P. test period is an indication of its ability, when -used on hypoid gears, to resist sending of the gears. Heretofore, to the best of my knowledge, no method has been devised, for accurately testing lubricants for E. P. value in advance of, or in lieu of placing the lubricant in actual service. By the application of my testing method, it is possible from the E. P. and fluid film ratings of individual oils to compoimd mixtures of such oils in proportions to give desired E. P. and full fluid film ratings. In this way, oils may be compounded to obtain products having certain desired characteristics.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I,

therefore, do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art. I

I claim as my invention:

1. The method of testing lubricants, which comprises rotating a cylindrical member between plane bearing surfaces under increasing bearing load, measuring the load and torque up to the point where the torque suddenly increases, continuing the rotation of said cylindrical member under predetermined increased load for a period of time and measuring the amount of wear produoed on the bearing surfaces.

2. The method of testing lubricants for E. P. value, which comprises relatively rotating bearing surfaces immersed in a lubricant to be tested under incremental increases in bearing load until the point of incipient seizure is reached, adjusting the bearing load to a predetermined figure, maintaining said load substantially constant during a definite time period and determining the rate of wear during such period.

3. The method of testing lubricants, which comprises diluting a given lubricant with an inert petroleum distillate in a definite proportion, rotating a bearing member between plane bearing surfaces while immersed'in said'diluted lubricant,

applying increased loads to said bearing aces until the point of incipient seizure of said surfaces is-reached, bringing the load to a predetermined amount thereafter, maintainingsaid load substantially constant during a continued test period of a definite duration, and measuring surfaces occurs, adjusting the applied load to a predetermined amount not greater than that at which the sudden torque increase occurred, continuing to run said bearing member while keeping the load constant at 'said predetermined amount and determining the rate of wear during such period.

' FREDERICK A. PAVILLE. 

